20-Year Mortgage Calculator (UK, 2026)
Work out the monthly repayment on a 20-year mortgage term — the middle ground between an aggressive 15-year payoff and the standard UK 25-year term. Defaults use Bank of England's recent quoted rate.
20 years vs other terms
Same £240,000 loan at 4.32% — what changing the term does to the monthly payment and lifetime interest:
| Term | Monthly | vs 20-year | Total interest | Interest vs 20-year |
|---|---|---|---|---|
| 10 years | £2,467 | +£971 | £55,986 | −£62,848 |
| 15 years | £1,814 | +£319 | £86,516 | −£32,317 |
| 20 years (this page) | £1,495 | — | £118,834 | — |
| 25 years | £1,310 | −£186 | £152,880 | +£34,046 |
| 30 years | £1,191 | −£305 | £188,584 | +£69,750 |
20-year monthly payments by loan size
At 4.32% over 20 years. Each row links to a full cost breakdown for that loan size:
| Loan | Monthly payment | |
|---|---|---|
| £100,000 | £623 | Full £100k cost guide → |
| £150,000 | £934 | Full £150k cost guide → |
| £200,000 | £1,246 | Full £200k cost guide → |
| £250,000 | £1,557 | Full £250k cost guide → |
| £300,000 | £1,869 | Full £300k cost guide → |
| £350,000 | £2,180 | Full £350k cost guide → |
| £500,000 | £3,115 | Full £500k cost guide → |
The 20-year sweet spot
A 20-year mortgage term sits between the aggressive 15-year payoff and the standard UK 25-year default. At today's rates it typically cuts lifetime interest by 25–35% versus 25 years, while adding a manageable amount to the monthly payment — use the comparison table above to see the exact figures for your loan.
It's a natural fit for second-steppers and remortgagors in their late thirties and forties: keep the payment affordable, but land mortgage-free before retirement age without needing the higher commitment of a 15-year schedule. Because interest is charged on the outstanding balance, the five years you shave off the standard term come almost entirely out of the interest-heavy tail of the mortgage — the years where payments barely dent the principal.
If you're mid-mortgage, the usual way to get to a 20-year schedule is at remortgage: ask for the shorter term, or keep the longer term and overpay — the mortgage comparison calculator models how overpayments shorten the effective term without the contractual lock-in.
How it's calculated
The monthly payment uses the standard amortising-loan formula used by every UK lender:
M = P × (i × (1+i)n) / ((1+i)n − 1)
where P is the loan (price minus deposit), i is the monthly rate (annual ÷ 12) and n is 240 payments (20 years × 12). Interest accrues on the outstanding balance, which is why shortening the term saves so much — see the full explanation on the main mortgage calculator.
Frequently asked questions
How much is a 20-year mortgage on £200,000?
At 4.32%, a £200,000 loan over 20 years costs about £1,246 a month with roughly £99,028 total interest — versus about £1,091 a month and £127,399 interest over 25 years.
Is a 20-year mortgage term worth it compared to 25 years?
On a £200,000 loan at 4.32%, dropping from 25 to 20 years adds about £155 a month but saves roughly £28,371 in interest over the life of the loan. Whether that's worth it depends on your monthly headroom.
Can I shorten my mortgage term from 25 to 20 years when I remortgage?
Yes — remortgaging is the usual moment to shorten the term. Your new lender re-runs affordability on the higher payment. Regular overpayments achieve a similar effect without locking in the commitment, if your lender allows them ERC-free (typically 10% of balance per year).
Related calculators & guides
- Mortgage calculator — any term, with a full rate × term payment matrix
- Mortgage comparison & overpayment calculator — products side-by-side, fees and overpayments modelled
- Affordability calculator — how much could you borrow?
- Stamp duty calculator — SDLT, LBTT and LTT with all surcharges
- How overpayments bend your equity curve
- How a 25-year mortgage actually amortises
This calculator is a general-information tool, not a mortgage offer or financial advice. Your actual rate depends on lender, LTV, credit profile, product fees and stress-test outcomes. Speak to a regulated mortgage adviser before committing. Source for default rate: Bank of England's monthly effective interest rates.